The warming, called an El Nino, is expected to lead to fewer Atlantic hurricanes, more rain next winter for drought-stricken California and southern states, and even a milder winter for the nation's frigid northern tier next year.

Elsewhere in the world, it can mean an even hotter year coming up, with billions of dollars in losses for food crops.

The National Oceanic Atmospheric and Administration Thursday issued an official El Nino watch.

NOAA Climate Prediction Center director Mike Halpert said the warming should be in place this summer.